System for characterizing tire uniformity machines and methods of using the characterizations

ABSTRACT

A tire uniformity machine includes an apparatus for receiving and rotating a tire. The apparatus includes opposed chuck assemblies for receiving, inflating and rotating the tire and a load wheel applied to the rotating tire to obtain tire test results. At least one characterizing device is associated with components of the apparatus to characterize forces of at least one of the components and the characterized forces are used in adjusting the tire test results.

TECHNICAL FIELD

The present invention relates generally to tire testing equipment. Inparticular, the present invention relates to characterizing componentsof a tire uniformity machine. Specifically, the present inventionrelates to using characterizations of the tire uniformity machine forevaluating tires during normal testing procedures.

BACKGROUND ART

Ideally, a tire is desirable to be a perfect circle, and interiorstiffness, dimensions and weight distribution and other features thereofshould be uniform around the circumference of the tire. However, theusual tire construction and manufacturing process make it difficult tomass produce such an ideal tire. That is, a certain amount ofnonuniformity in the stiffness, dimensions and weight distribution andother features occur in the produced tire. As a result, an undesirableexciting force is produced in the tire while the vehicle is running. Theoscillations produced by this exciting force are transmitted to thevehicle chassis and cause a variety of vehicle oscillations and noisesincluding shaking, fluttering, and sounds of the tire vibrations beingtransmitted inside the vehicle.

Industry standards are available for evaluating nonuniformity of a tire.In one method, a rotating drum, which serves as a substitute for theroad surface, presses against a rotatably held tire with a predeterminedpressing force (several hundred kilograms), or the tire is pressedagainst the rotating drum with the predetermined pressing force. Thetire and the rotating drum are capable of rotating around theirrespective rotational axes, in such a way that when either one rotates,the other is also caused to rotate.

In this condition, the tire or the rotating drum is rotatably driven sothat the tire rotates at 60 revolutions per minute. As the tire rotates,the exciting force produced by nonuniformity of the tire occurs. Thisexciting force is measured by one or more force measuring devices (suchas a load cell) mounted on a bearing which rotatably supports the tireor the rotating drum, or mounted on a member attached to this bearing.From the measured value, an index that serves to evaluate thenonuniformity of the tire is computed. This measurement is referred toas a uniformity measurement.

Tires on which measurements were performed are classified into those forwhich the nonuniformity obtained from the index is within tolerablelimits and those for which it is not. To the extent possible, tires forwhich the nonuniformity is outside of the tolerable limits are subjectedto processing to decrease the nonuniformity. Tires that have beenprocessed are then subjected to uniformity measurement again; those forwhich the nonuniformity is within tolerable limits are separated fromthose for which it is not.

Through the procedure described above, only tires judged to have“nonuniformity within tolerable limits” are selected and shipped tocustomers (or sent to the next step in the tire evaluation procedure).

Although current tire uniformity machines are believed to be effective,it is believed that further improvements can be obtained. Current tireuniformity machines provide test results that are sometimesinconsistent. In determining whether a uniformity machine is reliable, asame tire will be tested five times to ensure that the machineconsistently detects and measures any nonuniformities in the tire. Anadditional sampling of tires are also then subjected to the sameuniformity tests. From this collection of test results, various filterscan be generated and applied to production tires to filter actualresults. As skilled artisans will appreciate, filtering the test resultsundesirably adds time to the test procedure. Filtering also raisesconcerns that the filters may be set to exclude tires that areacceptable and, more problematically, tires that are not acceptable maybe passed to allowance. Therefore, there remains a need to accuratelyand quickly test a tire. As such, there is a need to characterizecomponents of a tire uniformity machine so that those characterizationscan be filtered out of the test results so as to more accurately andquickly pass tires to allowance that are acceptable and reject tiresthat are not acceptable.

SUMMARY OF THE INVENTION

In light of the foregoing, it is a first aspect of the present inventionto provide a system for characterizing tire uniformity machines andmethods of using the characterizations.

It is another aspect of the present invention to provide a tireuniformity machine, comprising an apparatus for receiving and rotating atire, the apparatus including opposed chuck assemblies for receiving,inflating and rotating the tire, and a load wheel applied to therotating tire to obtain tire test results, and at least onecharacterizing device associated with components of the apparatus tocharacterize forces of the components, wherein the characterized forcesare used in adjusting the tire test results.

Yet another aspect of the present invention is a method for testingtires, comprising receiving and rotating at least one control tire at atime in an apparatus, each control tire having a known characteristic,applying a component of the apparatus to the at least one control tireand generating a component load force, detecting an angular position ofthe component, correlating the angular position and the component loadforce, and generating a characteristic waveform of the component fromthe angular position of the component load force of the at least onecontrol tire.

BRIEF DESCRIPTION OF THE DRAWINGS

This and other features and advantages of the present invention willbecome better understood with regard to the following description,appended claims, and accompanying drawings wherein:

FIG. 1 is a schematic diagram of a tire uniformity machine according tothe concepts of the present invention;

FIG. 2 is a perspective drawing of a load wheel used in the tireuniformity machine;

FIG. 3 is a flow chart showing a load wheel characterization processaccording to the concepts of the present invention;

FIG. 4 is a load wheel characterization waveform utilizing knownspring-rate tires to obtain a prediction waveform used in the analysisof tires being tested by the tire uniformity machine;

FIG. 5 is a flow chart showing a spindle characterization processaccording to the concepts of the present invention;

FIG. 6 is an exemplary spindle characterization waveform used in theanalysis of a tire being tested by the tire uniformity machine; and

FIG. 7 is a flow chart illustrating testing of tires using the machinecharacterization waveforms.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring now to the drawings and in particular to FIG. 1, it can beseen that a tire uniformity machine is designated generally by thenumeral 10. The machine includes side frame members 12 which areconnected at respective ends by a horizontal bottom frame member 14 anda horizontal top frame member 16. The side frame members 12 and framemembers 14 and 16 form a box-like structure within which a tire,designated generally by the capital letter T is received, tested anddischarged.

A conveyor 18 is configured with rollers which have openingstherebetween upon which the tire T is delivered to the machine 10. Eachtire T includes a tread 24 adjacent substantially parallel sidewalls 26which have beads 28 forming an inner diameter of the tire.

The machine 10 includes an apparatus for receiving and rotating the tireand, in particular, a lower spindle and chuck assembly 32 and an upperspindle and chuck assembly 34. Both the lower and upper spindle andchuck assemblies are outfitted with removable rims 30 and 48 which canbe in various sizes as needed to fit the bead diameter of a tire. Thelower spindle and chuck assembly 32 is carried and supported by theframe members 12 and 14 and is positioned so as to engage the tire as itis supported by the conveyor 18. In particular the lower spindle andchuck assembly 32 includes a hydraulic unit 38 which provides a shaft 40that maintains a piston 42 contained within a cylinder 44. At theappropriate time, the hydraulic unit engages the tire and, in particularthe lower bead 28, through an opening in the conveyor 18 so as to movethe tire into a testing position.

The upper spindle and chuck assembly 34 receives the other side of thetire T on the rim 48 when the lower spindle and chuck assembly engagesthe facing sidewall 26 at the bead 28 of the tire on the rim 30 attachedto the lower spindle and chuck assembly. The spindle and chuck assembly34 includes a rim 48 which is rotated by a spindle 50, and the assembly34 may also include spindle bearings, a rim adapter and other associatedcomponents. The spindle 50 is driven by a motor 52 and aninterconnecting belt drive 54 which connects the spindle 50 to themotor.

Briefly, in operation, the tire is delivered along the conveyor 18 andstopped at the appropriate position so that the lower spindle and chuckassembly can engage the lower facing side of the tire T. The lower rimassembly then moves the tire into engagement with the upper rimassembly, whereupon the tire is inflated and then rotated to initiatethe testing process.

A tire encoder 56 is carried by the upper spindle 50 to monitor therotational position of the tire T during rotation. The encoder 56generates a signal A dividing the tire circumference into equal segmentsand a signal B indicating a fixed single position on the circumferenceat any given point in time.

A tire inflation system 64 includes an air pressure transducer 65 whichmonitors the air pressure of the tire and an air pressure regulator 66to regulate the tire pressure to a desired pressure. As previouslyindicated, after the chuck assemblies engage the tire, the tire isinflated by the inflation system to a desired pressure prior to testingof the tire. The air pressure transducer 65 generates a pressure signalC.

A load wheel 70 moves horizontally into and out of contact with the tireT so as to apply a load to the tire and test for tire uniformity. Asbest seen in FIG. 2, the load wheel includes a shaft 72 having a hole 74therethrough. The load wheel is constructed with at least twosubstantially parallel spaced apart plates 78, but it will beappreciated that a single plate or multiple plates could be used. Eachplate 78 may be provided with a number of openings 80 so as to reducethe weight of the load wheel. The outer diameter of the plates 78support a radial surface 82 which engages the tire tread as shown inFIG. 1. Skilled artisans will appreciate that the overall constructionof the load wheel, including the materials, welds, machining and thelike, affects the characteristics and operation of the load wheel 70and, in turn the machine 10. The same construction concerns are alsoapplicable to the other components of the machine 10 that contact andengage the tire—the upper spindle and chuck assembly 34, the upper rim48, the lower spindle and chuck assembly 32, the lower rim 30 and thetire inflation system 64. All of these components, no matter how slight,impact the test data collected from the tire during its testing process.

Returning back to FIG. 1, it can be seen that the load wheel is mountedwithin a carriage 88, which is maintained by the frame members, andmoved into and out of position to engage the tire by a motor and gearingassembly 76 also carried by the frame members 12. At least one load cell84 is associated with the load wheel 70 and detects the forces exertedby the tire on the wheel during rotational movement. Each respectiveload cell generates a load cell signal D and D′. It will be appreciatedthat a single load cell may be used but that additional load cells 84may be provided to confirm the readings of the first load cell signal,or share the force of the load, or to detect slight variations in thetire construction.

A load wheel encoder 86 is carried by the carriage 88 so as to monitorthe rotational or angular position of the load wheel. The encoder 86generates an encoder signal E.

A computer 92, through a controller 90, receives the signals A-E so asto characterize the particular components of the tire uniformity machineand/or acquire other detected measurements generated during the tiretesting process. As such, these signals perform their known function ofmonitoring the variable forces exerted by the tire under test and alsoto analyze the components of the tire uniformity machine which applyforces to the tire during testing. The controller 90 is also used togenerate signals that operate the motors, valves, servos, and converyorsneeded to move the tire T into the machine and ready it for testing. Thecontroller 90 is connected to a computer 92 which can display andcollect the data and also manipulate and analyze the data collected asrepresented by the signals A-E and any other data signals collected.Skilled artisans will appreciate that the controller 90 and computer 92may work in tandem or separately to control components of the machine 10and process and present the data collected into a format usable bymanufacturing personnel. Moreover, both the computer and the controllerinclude the necessary hardware, software and memory needed to implementand carry out the operations of the machine 10 and the characterizationprocesses to be described.

Generally, the monitoring of the particular components of the tireuniformity machine is done to characterize the machine's mechanicalbehavior, whereupon the computer removes the unwanted influences causedby the machine's mechanical condition during production tire testing.Utilization of the machine characterizations determines whether adetected measurement is suitable for use as a valid test result andthen, with an analysis based on the machine's mechanicalcharacterization, unwanted waveform properties can be removed which areattributable to the machine's mechanical parts, its measurementapparatus and so on. These unwanted waveform properties can now bespecifically identified by the computer and software processes. As such,the unwanted portions of the waveforms that detract from both theprecision of the measurement and its conformance (repeatability) toprior measurements can be adjusted for.

In order to implement the characterization process, reference is nowmade to FIG. 3, wherein a load wheel characterization process isdesignated generally by the numeral 100. In this process, a lowspring-rate tire, which has a known spring-rate value, is loaded intothe machine. For example, an 800 pounds/inch spring-rate tire is loadedinto the machine 10 at step 102. Next, at step 104 the computer 92,which maintains a buffer memory and which provides the needed hardware,software and other memory components to implement the characterizationprocess, prepares a buffer for receipt of data collected by any of thecomponents of the tire uniformity machine and, in particular signals A-Eand specifically the load cell signals D, D′ and the encoder signal E.As used herein, the “spring-rate” is the increase in radial force asmeasured on a loaded and inflated tire, for each unit of distance theload wheel advanced toward the spindle that carries the rotating tire.

As a load wheel can never be perfectly round, any amount of run outimposed onto a rotating tire by the load wheel thus exerts a measurableradial force directly relating to the tire's spring-rate. For a divisionof N evenly-spaced angles around the load wheel, this force is measuredand compiled into a waveform of N points that characterizes the forceeffect of the load wheel at that specific spring-rate. Any number of Npoints could be used, but in most embodiments at least one hundred Npoints are required. Accordingly, after the buffer prepared in step 104is ready, the machine rotates the tire, records the angular waveformforces at various angular positions of the load wheel at step 106.

During the loading process of the present embodiment, it will beappreciated that the tire is allowed to spin for at least one hundredrevolutions so as to allow the tire to warm up and settle into a staticposition on the load wheel. After the buffer has been established, thetire is allowed to spin for at least six hundred more revolutionswhereupon an M-point radial force waveform (usually 100 points), interms of M evenly-spaced angles around the tire, and the rotationalposition of the load wheel at the beginning of each waveform collection,in terms of N evenly-spaced angles around the load wheel, are recordedfor each revolution. Next, at step 108, the computer computes anN-waveform “Average Waveforms” buffer. This is done by examining thesaved rotational position of the load wheel for each waveform recorded.This rotational position is rounded to the nearest integer modulo N, andthis is designated as position P. For each position P, the computer 92computes the mean of all waveforms that were collected where thebeginning rotational position of the load wheel is P. This resultingaverage waveform is then stored as the P_(TH) waveform of the “AverageWaveforms” buffer.

Next, at step 109, the computer 92 computes a “Base Waveform.” This isdone by calculating the mean of all waveforms stored across all indexesof the N-waveform “Average Waveforms” buffer, and storing the result asthe “Base Waveform.”

Next, at step 110, the computer 92 computes a N-point “Summed Waveform”and saves this in the appropriate memory file in the computer 92 forlater comparison. In particular, for each of the N waveforms in the“Average Waveforms” buffer, there exist M points of data (beginning atload wheel position P) that contain radial force plus load wheel run outby virtue of how the waveform was recorded. To extract this load wheelrun out, the following steps are performed by the computer. For eachindex Q (from zero to M−1) in each of the N waveforms in the “AverageWaveforms” buffer, the load wheel position for that point is determinedby the equation (P+Q×N÷ (number of load wheel angles occupied by onerevolution of the tire, in terms of N)) rounded to the nearest integermodulo N, and this is designated index S. The point at the Q_(TH) indexin each of the N waveforms is subtracted by the point at the Q_(TH)index of the “Base Waveform” and is then added to the S_(TH) index inthe “Summed Waveform,” and at the same time a count of values for theS_(TH) index is also incremented. After the loop is completed, the pointat each index of the “Summed Waveform” is divided by the total count ofvalues added to that index, thus computing the average of the pointsadded to each individual index in the “Summed Waveform.” Finally, thecomputer saves the resulting “Summed Waveform” and spring-rate valuefrom step 102 to the computer's memory as the final load wheelcharacterization for the chosen spring-rate tire.

At step 114 the low spring-rate tire is unloaded from the machine 10.Next, at step 116 a high spring-rate tire is loaded into the machine.For example, the high spring-rate tire may have a 1,450 pounds/inch²spring-rate.

Then, at step 118 steps 104-110 are repeated for the high spring-ratetire so as to collect corresponding Average Waveforms and SummedWaveforms for the high spring-rate tire. Next, at step 120 the highspring-rate tire is unloaded.

At step 122 a load wheel characterization waveform from the SummedWaveforms for later comparison is generated. The resulting load wheelcharacterization waveform can then be applied to the current tire beingtested. This is done by subtracting the load wheel characterizationwaveform from the recorded tire test waveform.

Referring now to FIG. 4, it can be seen that characterization waveformsfor the low spring-rate tire, designated generally by the numeral 130,and the high spring-rate tire, designated generally by the numeral 132,are shown. These characterizations illustrate the particularout-of-roundness of the load wheel of the machine 10. As such, it willbe appreciated by skilled artisans that each load wheel has a differentcharacterization waveform when tested with a low spring-rate tire and ahigh spring-rate tire. In any event, these two high and low spring-ratewaveforms can be extrapolated to predict a characterization waveformassociated with a medium spring-rate tire. It is these medianspring-rate tires that will be under test by the tire uniformity machineand this prediction value can be utilized to adjust the uniformitymeasurements detected by the load cells under a normal test.

Referring now to FIG. 5, a spindle characterization process isdesignated generally by the numeral 150. As used herein, the termspindle characterization refers to the characterization of the entireupper spindle, spindle bearings, rim adapter (which is referred to inthis description as upper chuck) and the rim. In this process, a largenumber (L) of tires are tested so as to generate a table of waveformsthat can be normalized based upon the spring-rate of a tire. Although Lcan represent any number, it is believed that the value of L should beat least 750 to provide an accurate spindle characterization. In anyevent, by using an average from the table of waveforms, the controlleror computer can compute a spindle characterization waveform that can beused directly to subtract from the recorded test waveform and produce anaccurate picture of the tire's properties.

The process 150 starts at step 152 where a large number of tires aretested by the load wheel 70 and the waveforms for each tire tested aresaved in a buffer. This buffer may be referred to as “Tire Waveforms.”As in the load wheel characterization process, each waveform may becorrelated to M positions around the tire as detected by the tireencoder 56. It will be appreciated in the present embodiment that eachtest waveform has the load wheel characterization procedure alreadyfactored out of its waveform. Although in some embodiments, only thespindle characterization waveform may be used to adjust the waveform ofa tire being tested. In any event, no spindle characterization isfactored out at this time. At step 154, each M point in the testwaveform is divided by the spring-rate of the tire currently under test.In some embodiments, the tire currently under test may also be referredto as a control tire that is used in populating the “Tire Waveforms”buffer. In step 154, all of the tire waveforms in the Tire Waveformsbuffer are normalized to the same spring-rate. In other words, as eachtire is tested, that tire's spring-rate is used to divide each datapoint of the newly-inserted waveform. Skilled artisans will appreciatethat the spring-rate of the tire under test is determined by the signalsD, D′ generated by the load cells 84, 84′. At step 156, the resultingwaveform is stored in the next available index in the “Tire Waveforms”buffer. If all of the entries in the “Tire Waveforms” buffer are filled,then the oldest waveform test result is deleted from the buffer and thenewest waveform, i.e. the one being added, is kept so that there arealways L entries in the “Tire Waveforms” buffer.

At step 158, once the “Tire Waveforms” buffer has L entries, that buffercan be used to calculate the spindle characterization. This isaccomplished by taking the average of all L waveforms in the “TireWaveforms” buffer and calling this the “Average Waveform.” At step 160,each M point in the “Average Waveform” is then multiplied by thespring-rate of the tire currently under test. In other words, thenormalized average of the Average Waveform is multiplied by the currenttire's spring-rate. This results in generation of a spindlecharacterization waveform based on the current tire's spring-rate.

With the resulting spindle characterization waveform, the waveform canbe applied to the current tire being tested. This is done by subtractingthe spindle characterization waveform from the recorded tire testwaveform.

As seen in FIG. 6, an exemplary spindle characterization waveform isshown. As such, each tire's waveform is compensated by the spindlecharacterization waveform based on the tested tire's known spring-ratevalue so as to provide a final result that is then compared to the knowndesirable parameters for tire uniformity. Skilled artisans willappreciate that if the tire uniformity machine undergoes any mechanicalchanges or stress, such as changing the rims or other component of theupper chuck assembly or some physical impact event occurs, then the“Tire Waveforms” buffer should be reset and L number of tires once againbe tested before re-computing a spindle characterization.

Referring now to FIG. 7, a tire test utilizing machine characterizationwaveforms is designated generally by the numeral 200. In this process,the tire under test is loaded into the machine at step 202 and the loadforces are measured by moving the load wheel into contact with the tireas it rotates. These load forces are measured at step 204 and then atstep 206 the computer adjusts the measured load forces with theextrapolated characterization waveform determined in the load wheelcharacterization process 100 and/or the spindle characterization process150. After these load forces are adjusted, then at step 208 the adjustedwaveforms are checked against the test criteria which defines whethercertain values of the tire under test are within an acceptable range ornot. Then at step 210, the tire under test is marked as eitheracceptable or unacceptable with a pass/fail designation. Those tiresthat are passed are allowed to proceed in the tire production process,while the unacceptable tires are withdrawn from the manufacturingprocess and undergo further evaluation.

Based on the foregoing the advantages of the present invention arereadily apparent. By characterizing the components of the machine, thosecharacterizations can be used to accurately identify high spots and lowspots on the load wheel and/or adjust for spindle variations so as toaccurately determine the characteristics of a machine that is testing atire. These characteristics can be updated during the useful life of theload wheel or other machine changes to ensure that the measurementsbeing detected are accurate. This allows for adjustments to the testingparameters based on imperfections in the load wheel and other componentsof the machine so as to eliminate any out of roundness or other problemswith the machine. By accurately determining nonuniformity of a tireutilizing the machine characterization waveforms, the reliability of thetire test results are increased.

Thus, it can be seen that the objects of the invention have beensatisfied by the structure and its method for use presented above. Whilein accordance with the Patent Statutes, only the best mode and preferredembodiment has been presented and described in detail, it is to beunderstood that the invention is not limited thereto or thereby.Accordingly, for an appreciation of the true scope and breadth of theinvention, reference should be made to the following claims.

What is claimed is:
 1. A tire uniformity machine, comprising: anapparatus for receiving and rotating a tire, said apparatus includingopposed chuck assemblies for receiving, inflating and rotating the tire,and a load wheel applied to the rotating tire to obtain tire testresults; and at least one characterizing device associated withcomponents of said apparatus to characterize forces of at least one ofsaid components, wherein said characterized forces are used in adjustingthe tire test results.
 2. The machine according to claim 1, furthercomprising: a computer, said at least one characterizing devicegenerating a characterizing signal received by said computer which usessaid characterizing signal to adjust the tire test results.
 3. Themachine according to claim 2, further comprising: at least one load cellassociated with said load wheel, said at least one load cell generatinga load cell signal received by said computer for use in the tire testresults.
 4. The machine according to claim 3, wherein said computerreceives two different load cell signals from said load cell, whereinone said load cell signal represents forces generated by a first tirewith a first known spring-rate when the first tire is loaded by saidload cell and another load cell signal represents forces generated by asecond tire with a second known spring-rate when the second tire isloaded by said load cell, said computer generating a load wheelcharacterization waveform from said load cell signals which is used toadjust the tire test results.
 5. The machine according to claim 4,further comprising: an encoder associated with said load wheel andgenerating a positional signal received by said computer, said computerprocessing said positional signal and said load cell signals to generatesaid load wheel characterization waveform.
 6. The machine according toclaim 2, further comprising: at least one load cell associated with saidload wheel and generating a load cell signal received by said computerfor use in generating a current tire spring-rate; and an encoderassociated with a spindle extending from one of the chuck assemblies andgenerating a positional signal received by said computer, said computerprocessing said positional signals and said load cell signal to generatea spindle characterization waveform.
 7. The machine according to claim6, wherein said computer receives said positional signal and said loadcell signal for each tire tested and generates a Tire Waveforms buffer.8. The machine according to claim 7, wherein said computer averages thevalues in said Tire Waveforms buffer to generate an Average Waveformwhich is applied to the rotating tire's spring-rate, which is determinedby said load cell signal along with an angular position provided in saidposition signal, so as to generate a spindle characterization waveformwhich is used to adjust the tire test results.
 9. A method for testingtires, comprising: receiving and rotating at least one control tire at atime in an apparatus, each said control tire having a knowncharacteristic; applying a component of said apparatus to said at leastone control tire and generating a component load force; detecting anangular position of said component; correlating said angular positionand said component load force; and generating a characteristic waveformof said component from said angular position of said component loadforce of said at least one control tire.
 10. The method according toclaim 9, further comprising: receiving and rotating a test tire in saidapparatus; applying said component to the test tire and generating atest tire load force; detecting an angular position of the test tire andan angular position of said component; correlating said angularpositions with said test tire load force; generating a test tirewaveform of the test tire from said angular position of the test tireand said test tire load force; and adjusting said test tire waveformwith said characteristic waveform.
 11. The method according to claim 10,further comprising: receiving a first control tire having a first knownspring-rate in said apparatus; using a load wheel as said component toobtain a first component load force of said first control tire;receiving a second control tire having a second known spring-rate insaid apparatus; using said load wheel to obtain a second component loadforce of said second control tire; and extrapolating said characteristicwaveform from said first and second component load forces.
 12. Themethod according to claim 11, further comprising: positioning an encoderto detect said angular positions of said load wheel.
 13. The methodaccording to claim 10, further comprising: receiving a plurality of saidcontrol tires in said apparatus one at a time; using a chuck assemblywith a spindle as said component to correlate an angular position ofeach control tire; using a load wheel to obtain a spring-rate for eachcontrol tire; correlating said angular position and said spring-rate foreach control tire as a waveform and storing in a Tire Waveforms buffer;averaging said waveforms in said Tire Waveforms buffer to generate anAverage Waveform; and generating a spindle characterization waveformfrom said Average Waveform and a spring-rate of said test tire.
 14. Themethod according to claim 13, further comprising: adjusting said testtire waveform with said spindle characterization waveform.